Bottom-up approach: Start with the number of real customers, multiply by what they would pay, then narrow down to what is actually reachable and realistic. Every investor can follow this logic — and push back on the right assumptions.
Include every possible customer in India who could benefit from this product — no geography, no constraints. This is the theoretical ceiling.
Filter by geography, language, segment, and go-to-market reality. A Tier 1 city B2B SaaS product is not addressing all of India on Day 1.
This is your near-term forecast. Be honest — it should reflect team size, sales capacity, and existing channels. A SOM is not a wish, it is a plan.
Top-down approach: Start with a known industry figure and narrow down by percentage. Quicker to fill in, but harder to defend — investors will push back on the percentages. Use this as a sanity check alongside the bottom-up approach.
Use a published figure from IBEF, NASSCOM, or a reputable sector report. Cite the source — it makes the number defensible.
Filter by segment, geography, and product scope. Be conservative — arbitrary percentages are the first thing investors challenge.
Year 1–2 realistic share. For most early-stage companies this is well under 5%. Connect this directly to the go-to-market plan.
